This invention relates to the field of magnetic disk substrates. More particularly, the invention relates to an improved aluminum-based alloy memory disk sheet stock, magnetic recording substrate products made therefrom and a related method for making such memory disk products.
The hard magnetic disks used as memory media for data storage in computers require an extremely high quality material. Aluminum, specifically aluminum alloys, are a metal of choice, due to the relatively high strength, light weight, low cost and good surface finishing characteristics of such alloys. Aluminum-magnesium alloys have been used for some time as substrates for the magnetizable layers of many memory disks. U.S. Pat. Nos. 4,699,672, 4,722,872 and 4,751,958 are representative of the magnesium-containing, aluminum-based alloys used for such memory storage devices. Various ways to manufacture such sheet products are disclosed in these references. Some of the more common aluminum-based alloys currently used for this purpose include 5082, 5086 and 5182 aluminum (Aluminum Association designations). These alloys all have about 4 wt. % magnesium and some amount of manganese added thereto.
Advances in memory storage technology may necessitate further reductions in thickness and/or size of the magnetizable disk, or at least the magnetizable layers deposited on a disk substrate. At the same time, new technologies demand an increase in the density of information storable per disk.